1. Field of the Invention
This invention relates to a wire harness fixing structure in which when a wire harness covered with a flexible corrugated tube for wire protection purposes is installed on a vehicle body or the like, the wire harness can be prevented from being affected by vibrations.
2. Related Art
FIG. 7 shows a conventional wire harness structure. A corrugated tube 71 is made of a synthetic resin, and is in the form of a thin-wall cylinder, and has parallel grooves and ridges alternately arranged at equal intervals in a longitudinal direction thereof, the grooves and ridges being formed over an entire periphery of the corrugated tube. The corrugated tube 71 is highly bendable, and a plurality of wires 72 are passed through the interior of the corrugated tube 71, so that the corrugated tube 71 and the wires 72 jointly form a wire harness 73.
The corrugated tube 71 serves as a wire protection tube, and this corrugated tube 71, together with the plurality of wires 72, can be easily bent into conformity with a two- or a three-dimensionally curved panel 75 of a mounting portion 74 such as a vehicle body, and thus the corrugated tube 71 enhances the efficiency of the operation for installing the wire harness 73.
There are two types of corrugated tubes 71, and one type has a slit, while the other type has no slit. With respect to the type of corrugated tube 71 with the slit, the wires 72 can be easily passed through the corrugated tube, using the slit. With respect to the type of corrugated tube 71 having no slit, the operation for passing the wires 72 through the corrugated tube is cumbersome, but there is no fear that the slit may be opened, and besides there is no need to wind a vinyl tape around the corrugated tape.
One example of a corrugated tube fixing device (hereinafter referred to merely as “fixing device”) 76 is a clamp which presses the corrugated tube 71 against the panel 75 of the mounting portion 74. The fixing devices 76 need to be provided at least at bent portions of the mounting portion 74 such as the vehicle body. A band or the like can be used as such a fixing device.
The fixing device 76 is fixed to the mounting portion 74 by an elastic retaining clip, a screw or other means. The retaining clip has a pair of elastic retaining piece portions which are inserted into a hole in the panel 75, and are retained therein. In the case of using the screw, the screw is inserted into a hole in a bracket of the fixing device 76, and is threaded into a screw hole in the panel 75, thereby fixing the fixing device to the panel 75.
The wire harness 73 is installed on and along the curved surface of the mounting portion 74 such as the vehicle body, and the corrugated tube 71 is firmly fixed to the mounting portion 74 by the plurality of fixing devices 76 spaced from one another in the longitudinal direction of the corrugated tube. As a result, the wire harness 73 is firmly fixed to the mounting portion 74, and therefore the shaking of the wire harness 73 due to vibrations developing during the travel of the vehicle, the interference of the wire harness 73 with the vehicle body (the mounting portion 74), the generation of abnormal sounds due to these phenomena, etc., are prevented.
The wires 72 within the corrugated tube 71 are protected from rain water, dirt, etc., by the corrugated tube 71, and are extended, for example, along the vehicle body (74) to a predetermined portion such as an instrument panel, a floor or a door (a hinge-type door or a slide door), and are connected to electrical equipments or auxiliary equipments on this predetermined portion through connectors. See JP-A-2002-199558 Publication, for example.
However, in the case where one end of such a wire harness covered with the corrugated tube is connected to a terminal fixed to the vehicle body, while the other end of the wire harness is connected to a terminal fixed to a portion which vibrates together with an engine, the one end portion and the other end portion of the wire harness are different in condition of vibration. Namely, the vibration of the body-side connection portion of the wire harness is small, while vibration of the engine-side connection portion of the wire harness is large.
And besides, the wire harness is not fixed within the corrugated tube, and therefore when the one end portion and the other end portion of the wire harness vibrate in different manners, respectively, the wires slide in contact with the inner surface of the corrugated tube, and are damaged by the friction, thus inviting a problem that an insulating performance of the wires are lowered.
There is the type of wire harness in which a bundle of wires are covered at its outer periphery with a metal braid for the purpose of blocking electromagnetic waves. In this case, when one end portion and the other end portion of the wire harness vibrate in different manners, respectively, the braid slides in contact with the inner surface of the corrugated tube, and is damaged by the friction, thus inviting a problem that an electromagnetic wave-blocking performance of the braid is lowered. And besides, the wires slide in contact with the inner surface of the corrugated tube through a damaged portion of the braid, and are damaged by the friction, thus inviting a problem that the insulating performance of the wires is lowered.